Team Fortress 2

I can't seem to play servers with custom maps. I know TF2 automatically download maps I don't have but for some reason when I try to join a server with a custom map, the map takes ages to download eventually ending in "Missing map maps/ctf_custom_example.bsp, disconnecting" message, on some servers sometimes asking if I should blacklist server before this message. It's frustrating and dunno what the cause of this problem and want to play custom maps.

Any help? Also I am set to "Allow all custom files from this server" and Steam is permitted on my firewall.

Oh... well I know that I have "Allow all customs" on. I check and recheck again to see if I have any options ricked which I am unaware of thats causing this problem. I thought it was because of specific maps I can't auto-download but I really can't auto-download any new maps.

When i try to join this unuusal trade server is says Missing map "then the map name" ... disconecting please add me and tell me how to fix!

Do you have Source SDK for making maps? Do you have problems with joining servers with new maps? I would like to get into the map making business for TF2 but I can't enjoy new maps on TF2 with Source SDK.